Merge pull request #5250 from AvaloniaUI/tooltip-position-recalculation

Tooltip position recalculation

samples/ControlCatalog/Pages/SliderPage.xaml

@@ -22,6 +22,20 @@
                 IsSnapToTickEnabled="True"
                 Ticks="0,20,25,40,75,100"
                 Width="300" />
+        <Slider Name="SliderWithTooltip"
+                Value="0"
+                Minimum="0"
+                Maximum="100"
+                Width="300">
+          <Slider.Styles>
+            <Style Selector="Slider /template/ Thumb">
+              <Setter Property="ToolTip.Tip" Value="{Binding $parent[Slider].Value, Mode=OneWay, StringFormat='Value \{0:f\}'}" />
+              <Setter Property="ToolTip.Placement" Value="Top" />
+              <Setter Property="ToolTip.VerticalOffset" Value="-10" />
+              <Setter Property="ToolTip.HorizontalOffset" Value="-30" />
+            </Style>
+          </Slider.Styles>
+        </Slider>
         <Slider Value="0"
                 Minimum="0"
                 Maximum="100"

samples/ControlCatalog/Pages/ToolTipPage.xaml

@@ -6,7 +6,7 @@
         <TextBlock Classes="h1">ToolTip</TextBlock>
         <TextBlock Classes="h2">A control which pops up a hint when a control is hovered</TextBlock>
 
-        <Grid RowDefinitions="Auto,Auto"
+        <Grid RowDefinitions="Auto,Auto,Auto"
               ColumnDefinitions="Auto,Auto"
               Margin="0,16,0,0"
               HorizontalAlignment="Center">
@@ -38,6 +38,31 @@
                 </ToolTip.Tip>
                 <TextBlock>ToolTip bottom placement</TextBlock>
             </Border>
+            <Border Grid.Row="2"
+                    Grid.ColumnSpan="2"
+                    Background="{DynamicResource SystemAccentColor}"
+                    Margin="5"
+                    Padding="50"
+                    ToolTip.Tip="Hello"
+                    ToolTip.Placement="Top">
+              <Border.Styles>
+                <Style Selector="Border">
+                  <Style.Animations>
+                    <Animation Duration="0:0:2" IterationCount="Infinite">
+                      <KeyFrame KeyTime="0:0:0">
+                        <Setter Property="ToolTip.HorizontalOffset" Value="0" />
+                        <Setter Property="ToolTip.VerticalOffset" Value="-50" />
+                      </KeyFrame>
+                      <KeyFrame KeyTime="0:0:2" >
+                        <Setter Property="ToolTip.HorizontalOffset" Value="100" />
+                        <Setter Property="ToolTip.VerticalOffset" Value="50" />
+                      </KeyFrame>
+                    </Animation>
+                  </Style.Animations>
+                </Style>
+              </Border.Styles>
+              <TextBlock>Moving offset</TextBlock>
+            </Border>
         </Grid>
     </StackPanel>
 </UserControl>

src/Avalonia.Controls/ToolTip.cs

@@ -1,3 +1,4 @@
+#nullable enable
 using System;
 using System.Reactive.Linq;
 using Avalonia.Controls.Metadata;
@@ -21,8 +22,8 @@ namespace Avalonia.Controls
         /// <summary>
         /// Defines the ToolTip.Tip attached property.
         /// </summary>
-        public static readonly AttachedProperty<object> TipProperty =
+        public static readonly AttachedProperty<object?> TipProperty =
-            AvaloniaProperty.RegisterAttached<ToolTip, Control, object>("Tip");
+            AvaloniaProperty.RegisterAttached<ToolTip, Control, object?>("Tip");
 
         /// <summary>
         /// Defines the ToolTip.IsOpen attached property.
@@ -57,10 +58,10 @@ namespace Avalonia.Controls
         /// <summary>
         /// Stores the current <see cref="ToolTip"/> instance in the control.
         /// </summary>
-        internal static readonly AttachedProperty<ToolTip> ToolTipProperty =
+        internal static readonly AttachedProperty<ToolTip?> ToolTipProperty =
-            AvaloniaProperty.RegisterAttached<ToolTip, Control, ToolTip>("ToolTip");
+            AvaloniaProperty.RegisterAttached<ToolTip, Control, ToolTip?>("ToolTip");
 
-        private IPopupHost _popup;
+        private IPopupHost? _popup;
 
         /// <summary>
         /// Initializes static members of the <see cref="ToolTip"/> class.
@@ -70,6 +71,10 @@ namespace Avalonia.Controls
             TipProperty.Changed.Subscribe(ToolTipService.Instance.TipChanged);
             IsOpenProperty.Changed.Subscribe(ToolTipService.Instance.TipOpenChanged);
             IsOpenProperty.Changed.Subscribe(IsOpenChanged);
+
+            HorizontalOffsetProperty.Changed.Subscribe(RecalculatePositionOnPropertyChanged);
+            VerticalOffsetProperty.Changed.Subscribe(RecalculatePositionOnPropertyChanged);
+            PlacementProperty.Changed.Subscribe(RecalculatePositionOnPropertyChanged);
         }
 
         /// <summary>
@@ -79,7 +84,7 @@ namespace Avalonia.Controls
         /// <returns>
         /// The content to be displayed in the control's tooltip.
         /// </returns>
-        public static object GetTip(Control element)
+        public static object? GetTip(Control element)
         {
             return element.GetValue(TipProperty);
         }
@@ -89,7 +94,7 @@ namespace Avalonia.Controls
         /// </summary>
         /// <param name="element">The control to get the property from.</param>
         /// <param name="value">The content to be displayed in the control's tooltip.</param>
-        public static void SetTip(Control element, object value)
+        public static void SetTip(Control element, object? value)
         {
             element.SetValue(TipProperty, value);
         }
@@ -207,8 +212,8 @@ namespace Avalonia.Controls
         private static void IsOpenChanged(AvaloniaPropertyChangedEventArgs e)
         {
             var control = (Control)e.Sender;
-            var newValue = (bool)e.NewValue;
+            var newValue = (bool)e.NewValue!;
-            ToolTip toolTip;
+            ToolTip? toolTip;
 
             if (newValue)
             {
@@ -235,6 +240,23 @@ namespace Avalonia.Controls
             toolTip?.UpdatePseudoClasses(newValue);
         }
 
+        private static void RecalculatePositionOnPropertyChanged(AvaloniaPropertyChangedEventArgs args)
+        {
+            var control = (Control)args.Sender;
+            var tooltip = control.GetValue(ToolTipProperty);
+            if (tooltip == null)
+            {
+                return;
+            }
+
+            tooltip.RecalculatePosition(control);
+        }
+
+        internal void RecalculatePosition(Control control)
+        {
+            _popup?.ConfigurePosition(control, GetPlacement(control), new Point(GetHorizontalOffset(control), GetVerticalOffset(control)));
+        }
+
         private void Open(Control control)
         {
             Close();

src/Avalonia.Controls/ToolTipService.cs

@@ -51,10 +51,12 @@ namespace Avalonia.Controls
             if (e.OldValue is false && e.NewValue is true)
             {
                 control.DetachedFromVisualTree += ControlDetaching;
+                control.EffectiveViewportChanged += ControlEffectiveViewportChanged;
             }
             else if(e.OldValue is true && e.NewValue is false)
             {
                 control.DetachedFromVisualTree -= ControlDetaching;
+                control.EffectiveViewportChanged -= ControlEffectiveViewportChanged;
             }
         }
         
@@ -62,6 +64,7 @@ namespace Avalonia.Controls
         {
             var control = (Control)sender;
             control.DetachedFromVisualTree -= ControlDetaching;
+            control.EffectiveViewportChanged -= ControlEffectiveViewportChanged;
             Close(control);
         }
 
@@ -97,6 +100,13 @@ namespace Avalonia.Controls
             Close(control);
         }
 
+        private void ControlEffectiveViewportChanged(object sender, Layout.EffectiveViewportChangedEventArgs e)
+        {
+            var control = (Control)sender;
+            var toolTip = control.GetValue(ToolTip.ToolTipProperty);
+            toolTip?.RecalculatePosition(control);
+        }
+
         private void StartShowTimer(int showDelay, Control control)
         {
             _timer = new DispatcherTimer { Interval = TimeSpan.FromMilliseconds(showDelay) };